Controversial opinion incoming: perhaps the audience for sites like 4chan/8chan reflects a curiosity created to some extent by the ever narrowing range of permitted news topics allowed by the MSM.
Think of Gab for example. The site has been described as "extremist friendly" or a "safe haven" for neo-Nazis, white supremacists, and the alt-right. The only reason the site exists in the first place, is that those people were pushed out from Twitter, outside of the realm of "allowed" mainstream opinions. The problem is that by pushing them out, you don't make them disappear, you make them less visible and more radicalised and dangerous.
So what is new? The internet is 30 years old now. So that's not new.
My controversial opinion is this: Pro-military and nationalist propaganda campaigns by the military since 2001, including a major push into video games, has radicalized a disenfranchised youth, who are seeing their world worse off than their parents. In other words, a military recruitment campaign went awry.